Abdominal muscle exerciser



FIG. 1 is a top, side and end perspective view of the abdominal muscle exerciser showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof, the opposite side being a mirror image of FIG. 4;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for an abdominal muscle exerciser, as shown and described. 